# CVE-2021-20208: Privilege escalation in cifs-utils

> A container user can access host Kerberos credentials when mounting CIFS, leading to privilege escalation and data compromise.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** ALPINE-CVE-2021-20208, AZL-6354, DEBIAN-CVE-2021-20208, GHSA-jx7v-8q27-738q, MGASA-2021-0277, OESA-2021-1193, SUSE-SU-2021:1159-1, SUSE-SU-2021:1161-1, UBUNTU-CVE-2021-20208

## What is CVE-2021-20208?

CVE-2021-20208 is a medium-severity vulnerability in Fedoraproject Fedora, published on 19 Apr 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A flaw was found in cifs-utils in versions before 6.13. A user when mounting a krb5 CIFS file system from within a container can use Kerberos credentials of the host. The highest threat from this vulnerability is to data confidentiality and integrity.

Weakness: CWE-269 (Improper Privilege Management), CWE-266 (Incorrect Privilege Assignment)

## Which versions are affected by CVE-2021-20208?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `cifs-utils` | SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 6.9-5.9.1 |
| `cifs-utils` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 6.9-13.14.1 |
| `cifs-utils` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 6.9-13.14.1 |
| `cifs-utils` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 6.9-13.14.1 |

Products: Fedoraproject Fedora, Redhat Enterprise Linux, Samba Cifs-Utils.

## How do I fix CVE-2021-20208?

Upgrade to a fixed version.

## Is CVE-2021-20208 being exploited?

There is no known exploitation of CVE-2021-20208 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20208 and fix it if it is affected.

What it is: CVE-2021-20208 is a medium-severity vulnerability in Fedoraproject Fedora, published on 19 Apr 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-20208 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-20208/ (Markdown: https://insights.sbomify.com/CVE-2021-20208/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20208
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20208
- OSV: https://osv.dev/vulnerability/CVE-2021-20208

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20208/
Summaries are generated and may contain mistakes; the official description above is the record.